Within the field of cutting tools used in turning operations, there are many examples of reversible cutting inserts removably retained in an insert receiving pocket of a tool holder, either directly or by employing a shim. In some instances, these reversible cutting inserts are configured such the abutment surfaces associated with the opposing end surfaces are lower than the corner cutting edges.
U.S. Pat. No. 8,568,064 discloses a trigonal-shaped double-sided indexable cutting insert and a correspondingly shaped support plate. In one embodiment, the support plate has an upper surface with three separate flat contact surfaces defining an upper central plateau, with the upper central plateau being located above its adjoining transitional faces and upper edges. The upper and lower surfaces of the cutting insert each have three flat contact faces associated with its corner regions, which are recessed with respect to its corner cutting edges, and which are configured to engage the upper central plateau of the support plate in each index position.
US 2012/0114435 discloses a rectangular-shaped double-sided indexable cutting insert and a correspondingly shaped reinforcing part. The reinforcing part has four flat portions formed between the outside of a ring shaped elevated portion and each corner of the rectangle. The upper and lower surfaces of the cutting insert each have four dome-shaped convex portions associated with its corner regions, which are recessed with respect to its corner cutting edges, and at least three of which engage the four flat portions in each index position.